In some situations such as in clinical practice, sensors for monitoring a respiratory status of a patient are required.
Therefore, there is proposed a sensor including a polyvinylidene difluoride (PVDF) film having conductor layers on both sides, and electrodes provided on the both sides of the PVDF film (e.g., Japanese Patent No. 4989932). A sensor of this type evaluates presence or absence of breath based on a temperature change of the PVDF film due to a breath blown against the PVDF film.